Plug-in base



Oct- 19, 1965 R. w. THOMAS ET AL 3,213,407

PLUG-IN BASE 4 Sheets-Sheet 1 Filed March 7, 1963 Oct. 19, 1965 R, w. THOMAS ET AL 3,213,407

PLUG-IN BASE 4 Sheecss-SheeiI 2 Filed March 7, 1963 4 Sheets-Sheet 5 @n NF) X .IJ f RE R. W. THOMAS ET' AL PLUG-IN BASE m 6%.mmll iw @E www O7. mw Nw tF Mw mM NN Nk @u m. w@ .umwulmlg M 0 Nh ,Nulim 0^ F SHE .umhwl Oct. 19, 1965 Filed March 7, 1965 Oct- 19, 1965 R. w. THOMAS ET AL 3,213,407

PLUG-IN BASE 4 Sheets-Sheet 4 Filed March 7, 1963 mi 'N l INVENTORS ,M55/Q7 TAW/Va" A64/v@ /w/ffy United States Patent O 3,213,407 PLUG-IN BASE Robert W. Ihonias, St. Clair Shores, and Frank Krissy,

Birmingham, Mich., assignors to I-T-E Circuit Breaker Company, Phiiadeiphia, Pa., a corporation of Pennsylvania Filed Mar. 7, 1963, Ser. No. 263,642 S Claims. (Cl. 339-492) The instant invention relates to motor starters in general and more particularly to a base for mounting one o-r more overload relays of a motor starter.

Motor starters of the type described in copending application Serial No. 189,915, tiled April 24, 1962, entitled Electrical Device, in the name of J. B. Cataldo et al. and assigned to the assignee of the instant invention are provided With electromagnetic contactors and one or more overload relays in series with the contactor operating coil. The overload relay is a normally closed device having overload responsive means to automatically open the relay upon the occurrence of predetermined overload conditions. The opening of the relay serves to open the energizing circuit for the contact-or coil and as a result the contactor opens.

The motor starter construction disclosed in the aforesaid copending application Serial No. 189,915 consists of an arrangement in which the contactor and overload relays are mounted to a common base with the combined width of the relays being no wider than the Width of the contactor. The contactor is a three pole unit. For some installations individual Overload relays are required for each pole while for other installations only one or two overload relays will sutiice for all three poles.

The instant invention provides a novel construction for a plug-in base to mount one or more overload relays for operation with a contactor to form a motor starter. Briefly, the plug-in base of the instant invention comprises a main portion having three sets of plugin connectors to receive stabs projecting from the bottom of the overload relays. Connections internal to the base suitably interconnect the plug-in connectors so that with three closed overload relays mounted to the base a complete series circuit is formed between two control terminals mounted to the side leg of the base. The plug-in connectors of the base and indexing means Carried by the base position each of the overload relays for ready electrical connection to the main terminals of the contactor.

The plug-in connectors of the base are integrally formed with conducting straps to constitute an economically produced jumper means. This structure is stamped from conducting sheet material with the strap portion having an upturned connector portion at one -or both ends thereof. A slot beginning at the free end of the connector portion extends into the strap portion and divides the connector portion into two spaced apart legs.

The overload relay stabs are also constructed of sheet material and are received in the space between the connector legs being positioned at right angles to the connector. As the stab enters the space, the legs yield and because of the resilient nature of the material forming the jumper means, the legs are spring presse-d firmly against the stab thereby forming a good electrical connection.

Accordingly, a primary object of this invention is to provide a novel construction for a plug-in base.

Another object is to provide a plug-in base having a novel construction for stab receiving terminals.

Still another object is to provide a jumper means including a conducting portion and integrally formed connector means.

Still another object is to provide a one piece connector melans and conducting strap constructed of sheet materia 3233,47 Patented Oct. 19, 1965 A still further object is to provide a plug-in base arrangement to which as few as one and as many as three overload relays may be mounted.

These as well as further objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE l is an exploded perspective illustrating the relationship between a single overload relay and a plug-in bus constructed in accordance with the teachings of the instant invention.

FIGURE 1A is an enlarged fragmentary plan View of the plug-in base showing a stab receiving aperture thereof.

FIGURE 2 is a plan View of a motor starter assembly including the plug-in base of FIGURE l and three overload relays.

FIGURE 3 is a plan view of the plug-in base of FIG* URE 1.

FIGURE 4 is an end view of the plug-in base looking in the direction of arrows 44 of FIGURE 3.

FIGURE 5 is a side view of the plug-in base looking in the direction of arrows 5 5 of FIGURE 3.

FIGURE 6 is a bottom view of the plug-in base with its cover removed.

FIGURES 7a, 7b and 7c are a plan view, an end view, and a side View, respectively, of a jumper means having plug-in connectors at both ends thereof.

FIGURES 8a, Sb and 8c are a plan view, an end view and a side view, respectively, of a jumper means having a plug-in connector at only one end thereof.

FIGURE 9 is a plan View of the plug-in base with only two overload relays mounted thereon.

FIGURE l0 is a side elevation of a shorting clip which is mountable to the plug-in base in the absence of an overload relay.

Now referring to the figures. Motor starter 10 (FIG- URE 2) is a three phase unit including line terminals 11A, 11B, 11C connected in electrical series with load terminals 12A, 12B and 12C, respectively. For example, the connection 4between terminals 11A and 12A is through one phase of contactor 13 and the heater circuit of overload relay 14A. Load terminals 12A, 12B and 12C of motor starter 10 are each an individual main terminal of different overload relays provided for each phase of motor starter 1i). The other of the L-shaped relay terminals 15A, 15B and 15C, respectively, are electrically land mechanically connected to contactor load terminals 16A, 16B and 16C by screw means 17.

As best seen in FIGURE l, overload nel-ay 14B is provided wit-h contr-ol circuit stabs 17B, 18B extending downwardly from the bottom yot the insulating relay (housing 119. The overload relays 14A, 14B and 141C are -of identical construction and are shown in FIGURE 2 a-s .being mounted to plug-in base 20. Main portion 21 of plug-in base `2i) `is provided with three rows of apertures (FIG- URE 3) with the apertures in the rst row being designated 22A, I22B and 22C; #the apertures in the second row being ,designated 23A, 23B and 23C; yand the apertures in the third row being Idesignated 24A, 24B |and 24C. Each aperture in each .of the rows is :aligned with an apertune in each of the other rows. Thus, i-t is seen in FIG- URE l that 'base apertures 22B and 23B are positioned and constructed to receive control circuit stabs 171B and 18B, respectively, while indexing aperture 24B is -positioned to reoeive yindexing projection 19B which extends downwardly from the bottom of overload relay housing 19. As will :be more fully explained, there is la stab receiving connector aligned with each of the base apertures 22A, 22B, and 22C; 23A, 23B and 23C, to electrically engaged overload relay stabs :entering tlhe respective apertures.

The enlarge-ment of FIGURE 1A clearly lillustrates that a stab receiving aperture of a plug-in base 22 is crucifor-m v 3 consisting -o'f a first elongated portion 26 and a second elongated portion 27 crossing portion 26 at right angles thereto and at the center thereof. P-ortion 26 receives the overload relay stab while portion L27 lpositions the stab receiving connector 'which engages the overload relay stab.

As seen in FIGURE-6, jumper means 3-1 extends between base `apertures 22A and 23B while jumper means 32 extends 'between base apertures 22B .and 23C. Each of the jumper means 31 and 32 lis provided with stab receiving connectors `at both ends thereof as will be hereinafter explained. Jumper means 33 land 34, each having but .a single connector, `are associated with base apertures 23A and 22C, respectively. Insulation covered conductor 35 connects ju-mper means 33 to .an extension of control terminal 36 while insulation covered conductor 37 connects an extension of control terminal 38 to jumper means 34.

`For the assembly illustrated in FIGURE 2 there is a complete series circuit between control terminals 36 .and 3S when 'all of the overload relays 14A, 14B and '14C are closed. This circuit is as lfollows: From control termin-al 36 through conductor 35, jumper means 33, overload relay 14A, jumper means 31, overload relay 14B, jumper means 32, overload relay 14C, jumper means 34, and conductor 37 to control terminal 38.

Control terminals 36 and 38 are mounted to the stepped side portion 3-9 of base 720 which extends upwardly at right angles to main portion 21 and is positioned parallel to the overload relays. Apertures 41 of main portion 21 are provided to' receive fastening means (not shown) which secures plug-in bus to a mounting surface. Apertures 42 in main .portion 21 are provided to receive fastening means 99 which secures sheet-like cover 43 to main portion 21. With cover 43 secured in place, jumper means 31 through 34 and insulation covered conductors 3S and 37 Iare maintained in their operative positions in the bottom recesses of the main portion 21 of plug-in base 20. Screw 4'5 provides lthe electrical connection between control terminal 36 and one terminal of the contactor operating coil.

FIGURES 7a, 7b and 7c illustrate details of construction for jumper means 31. Jumper means 31 is constructed .of conducting sheet material and includes an elongated conducting st-rap 51 having stab receiving connectors 52 at each end of strap 51. Both connectors 52 exten-d in the same direction trom strap 51 at right angles thereto. Slot 53 extends from the tree end of connector A52 the full length thereof yand partway into str-ap 51 thereby dividing connector 52 into spaced parallel legs 54, S5. The end of slot 53 at th-e lfree end of connector 52 ares outwardly to provide a wide mouth opening to receive a terminal stab. This Haring enables a cam-like .action to take ,place .as a relay terminal stab enters slot 53. The terminal stab is Wider than the space Ibetween the inward projections 54', 55 of legs 54 yand 55 so that as the terminal stab enters slot 53 legs 54 yand 55 are forced Iaside. The conducting material of which jumper means 31 is constructed is also resilient so that Ias legs 54 and 55 are spread `a biasing force i-s established Aurging these legs inwardly toward one another. This forces projections 54', 55 to bear firmly against the sides of the terminal stab thereby forming a good electrical connection.

FIGURES 8a, 8b .and 8c illustrate details of construction for jumper means 33. Jumper means 33 includes conducting strap portion 711 to which insulation covered lead is soldered. Integrally formed with strap portion 7:1 is stab receiving connector 72 extending .at right angles to portion 71 at one end thereof. The construction of connector 7:2 is identical to the construction of connector 52 previously described.

In the event that one .or more of the overload relays 14A, 14B, 14C are eliminated, the overload relay so eliminated may be replaced yby a shortin-g clip 60 (FIGURE 10). Clip 60 is constructed olf electrically conducting material and is of generally U-shape with the 4arms lof the U being the same size as the overload relay control circuit stabs and being spaced apart by the same distance.

For example, in FIGURE 9 the center overload relay 14B has 'been eliminated and replaced by shorting clip `60. rIlhe arms 67 and 68 of clip i60 extend through base apertures @2B and 23B, respectively, to engage the contacts in alignment with the respective apertures. Screw means 611 received by threaded aperture 62 in base porftion 21 extends through shortin-g clip aperture 63 to mechanically fasten clip 6i) to base .20. Thus, it is seen that -any or 'all of Ithe overload relays 14A, 114B and 14C may be replaced by individual shorting clips 60 in order to preserve continuity between control circuit terminals 3'6 and 38.

In lthe foregoing there has been described a novel construction for a plug-in baise to .receive overload relays which are combined with a contactor to Iform a motor starter. The internal electr-ical connections for the base lare provided with integrally torrned stab receiving plug-in connectors which are, io-f novel construction yet materially reduce costs of manufacturing the connectors and also reduce costs in lassemblying the plug-in base.

Although there has been described a preferred embodiment of this novel invention, many variation-s and modications will now be apparent .to those skilledin the art. Therefore, this invention is to be limited, not by the speciiic disclosure herein, but only by .the appending claims.

The embodiments of the invention in which an eX- clusive privilege or property is claimed are defined as follows:

1. A plug-in base for reception of a preselected number of overload relays comprising:

a slab-like member constructed of insulating material, one face of said slab-like member having a plurality of rows of cruciform shaped apertures therein;

a stab receiving connector aligned within each aperture of each of said rows and disposed internally of said slab-like member, each of said connectors comprising spaced legs disposed in opposite arms of its respective cruciform shaped aperture, similarly located connectors from each of said rows cooperating to define a plurality of overload relay stab receiving pairs;

a plurality of conducting straps disposed within said slab-like member, each electrically connecting one of said connectors of one of said receiving pairs with one of said connectors of another of said receiving pairs to establish an electrical series circuit when the stabs of associated overload relays are received by said plurality of receiving pairs; l

and a pair of upstanding terminals each electrically connected to a connector of a different overload relay stab receiving pair and each directed away from said one face of said slab-like member to provide an easily accessible terminal arrangement for connecting. a source of electrical current to said electrical serles circuit.

2. The device of claim 1, and further including at least one U-shaped shorting clip, the arms of which may be inserted within the connectors of one of said plurality of overload relay stab receiving pairs to provide a short circuit therebtween and thus selectively alter the number of overload relays said receiving pairs may accommodate.

3. The device of claim 1, wherein each of said cruciform apertures includes rst and second crossed sections and each of said connectors includes spaced legs disposed in opposite extremities of said irst section, said second section and the confronting edges of said spaced legs cooperating to form a releasably clamping stab receiving location.

4. The device of claim 1, wherein each of said plurality of overload relay stab receiving pairs comprises a first connector located in a rst of said plurality of rows of apertures and a second connector similarly located in a second of said plurality of rows of apertures, said conducting straps integrally connecting said rst connectors of one of said plurality of overload relay stab receiving pairs with said second connector of an adjacent overload relay stab receiving pair, said legs of said rst connector of said one of said pairs and said legs of said second connector of said adjacent pair being at opposite ends of said straps and extending transverse thereto.

5. The device of claim 4, wherein the spaced legs of said first and second connectors are provided with confronting inward projections disposed intermediate the ends of said legs.

6. In combination:

a slab-like member constructed of insulating material, one face of said slab-like member having a plurality of rows of cruciform shaped apertures therein;

a stab receiving connector aligned within each aperture of each of said rows and disposed internally of said slab-like member, each of said connectors comprising spaced legs disposed in opposite arms of its respective cruciform shaped aperture, similarly located connectors from each of said rows cooperating to define a plurality of coverload relay stab receiving pairs;

at least one overload relay having a pair of stabs depending therefrom, said pair of stabs being disposed within the connectors of one of said overload relay stab receiving pairs;

a plurality of conducting straps disposed with said slablike member, each electrically connecting one of said connectors of one of said receiving pairs with one of said connectors of another of said receiving pairs to establish an electrical series circuit between said plurality of overload relay stab receiving pairs;

and a pair of upstanding terminals each electrically connected to a connector of a diiferent overload relay stab receiving pair and each directed away from said one face of said slab-like member to provide an easily accessible terminal arrangement for connecting a source of electrical current to said electrical series circuit.

7. The device of claim 6 and further including at least one U-shaped shorting clip, the arms of which may be inserted within the connectors of one of said plurality of overload relay stab receiving pairs to provide a short circuit therebetween and thus selectively alter the number of overload relays said receiving pairs may accommodate.

8. The device of claim 7, wherein each of said plurality of overload relay stab receiving pairs comprises a rst connector located in a first of said plurality of rows of apertures and a second connector similarly located in a second of said plurality of rows of apertures, said conducting straps integrally connecting said frst connectors of one of said plurality of overload relay stab receiving pairs with said second connector of an adjacent overload relay stab receiving pair, said legs of said rst connector of said one of said pairs and said legs of said second connector of said adjacent pair being at opposite ends of said straps and extending transverse thereto.

References Cited by the Examiner UNITED STATES PATENTS 1,122,575 12/ 14 Cook et al. 1,518,733 12/24 Eckstein 339-210 X 1,569,869 1/26 McIntosh 339-155 X 2,349,629 5/44 Lazich et al. 339-19 X 2,664,552 12/53 Ericsson et al. 339-192 2,766,438 10/56 Kohler et al 339-256 2,965,869 12/60 Ludwig 339-33 3,031,640 4/62 McKee 339-258 X FOREIGN PATENTS 811,085 4/59 Great Britain. 531,232 4/55 Italy.

JOSEPH D. SEERS, Primary Examiner. 

1. A PLUG-IN BASE FOR RECEPTION OF A PRESELECTED NUMBER OF OVERLOAD RELAYS COMPRISING: A SLAB-LIKE MEMBER CONSTRUCTED OF INSULATING MATERIAL, ONE FACE OF SAID SLAB-LIKE MEMBER HAVING A PLURALITY OF ROWS OF CRUCIFORM SHAPED APERTURES THEREIN; A STAB RECEIVING CONNECTOR ALIGNED WITHIN EACH APERTURE OF EACH OF SAID ROWS AD DISPOSED INTERNALLY OF SAID SLAB-LIKE MEMBER, EACH OF SAID CONNECTORS COMPRISING SPACED LEGS DISPOSED IN OPPOSITE ARMS OF ITS RESPECTIVE CRUCIFORM SHAPED APERTURE, SIMILARLY LOCATED CONNECTORS FROM EACH OF SAID ROWS COOPERATING TO DEFINE A PLURALITY OF OVERLOAD RELAY STAB RECEIVING PAIRS; A PLURALITY OF CONDUCTING STRAPS DISPOSED WITHIN SAID SLAB-LIKE MEMBER, EACH ELECTRICALLY CONNECTING ONE OF SAID CONNECTORS OF ONE OF SAID RECEIVING PAIRS WITH ONE OF SAID CONNECTORS OF ANOTHER OF SAID RECEIVING PAIRS OF ESTABLISH AN ELECTRICAL SERIES CIRCUIT WHEN THE STABS OF ASSOCIATED OVERLOAD RELAYS ARE RECEIVED BY SAID PLURALITY OF RECEIVING PAIRS; AND A PAIR OF UPSTANDING TERMINALS EACH ELECTRICALLY CONNECTED TO A CONNECTOR OF A DIFFERENT OVERLOAD RELAY STAB RECEIVING PAIR AND EACH DIRECTED AWAY FROM SAID ONE FACE OF SAID SLAB-LIKE MEMBER TO PROVIDE AN EASILY ACCESSIBLE TERMINAL ARRANGEMENT FOR CONNECTING A SOURCE OF ELECTRICAL CURRENT TO SAID ELECTRICAL SERIES CIRCUIT. 